Flocced mineral materials can be used to prepare high temperature resistant, water resistant materials. These non-asbestos materials can be prepared as described in U.S. Pat. No. 4,239,519 and No. 4,707,298. In particular U.S. Pat. No. 4,707,298 describes how lithium in lithium fluorhectorite can be exchanged with guanidinium ions to provide films with good flexibility and wet strength.